Research & Presentations
Three Brachial Plexus Injury Subjects’ Function After One(+) Year of Upper-Extremity Myoelectric Orthosis Treatment By David R. Coleman, CPO, FAAOP
Introduction Traumatic brachial plexus injury (TBPI) is a rare dysfunction causing myriad impairments to the ipsilateral upper extremity (UE) of an individual. 1 Impairments result from a distractive force at the shoulder complex deranging the nerves and disrupting their ability to communicate afferent and efferent signals. Young males are at the highest risk for TBPI because of their incidence of motor-vehicle accident (MVA) or other high-impact traumas, though anyone is vulnerable.2 Disruptions can present as preganglionic avulsion, rupture, neuroma, or neurapraxia1-5 (Figure 1). Treatments vary depending on intact innervations, but the most severe dysfunction and most invasive interventions occur with avulsions.4-6 Elbow flexion is impaired in 95 percent of cases of TBPI due to C5-C6 avulsion or rupture.4 Our ultimate goal as a health-care team is to have our clients achieve normal (M5) or like-normal (M4) elbow flexion on the manual muscle testing (MMT) scale. Many surgical interventions are available, including muscle graft, muscle transfer, nerve graft, and nerve transfer. Which intervention is used is determined from available muscles and nerves, and a degree of compromise regarding impairment in
Figure 1 Traumatic brachial plexus injury
the donor site.1,3-6 Because of the extent of damage from MVAs, the chance of restoring function may mean pursuing interventions with low success rates. Motor and sensory deficits in the donor sites must be weighed against the prospective increase in value for the client. There are many validated nerve and muscle transfers, but a couple are typically utilized as a last resort. One treatment is the intercostal nerve (ICN) transfer to the musculocutaneous nerve (MCN) because of the presence of both motor and sensory neurons, and because the number of axons is similar to how many innervated the brachialis. 3-6
Donor-site deficits are inconsequential since they only contribute accessory function to inspiration.4 Far more substantial is the client’s need to perform the inherent action of the nerve to produce muscle activity at the transfer site— meaning muscle recruitment involves a deep breath or Valsalva maneuver. Muscle transfers often utilize the gracilis muscle for a donor muscle due to lack of noticeable deficit once harvested. Unfortunately, the ICN transfer is only 46 percent successful at achieving M4 or M5 function with intact elbow flexion muscles.4 With gracilis muscle transfer, the success rate is diminished further.
O&P News | May 2018
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